Method and apparatus for preshaping raw logs

ABSTRACT

In each of the intersections between the outer surface of a raw log and a plurality of longitudinal sectional planes passing through the center axis of the log, that point which is nearest the center axis is detected, and the log is so cut that, in each of the sectional planes, all points in the resulting outer line are at the same distance from the center axis as the above mentioned nearest point, whereby the raw log is preshaped into a columnar shape of the same coaxial cross section over the entire length thereof. By rotary cutting this preshaped log, rectangular veneer pieces without waste edge parts can be obtained before the log becomes a true circular cylinder.

Noriyulti et a1.

Got. 22, 1974 1 1 METHOD AND APPARATUS FOR PRESHAPING RAW LOGS [75] Inventors: Nagaoka Noriyuki; Niimi l-laruo,

both of Aichi, Japan 22 Filed: July 12, 1972 21 Appl. No.: 271,201

[30] Foreign Application Priority Data July 13, 1971 Japan 46-51480 July 15, 1971 Japan 46-52549 [52] US. Cl. 144/309 R, 144/3 R, 144/209 A [51] int. Cl B271 5/02 [58] Field of Search 144/209 A, 209 R, 3 R, 144/309 R [56] References Cited UNITED STATES PATENTS 2523,56 9/1950 Foreman 144/209 A Brookhyser H 144/209 R Mason 144/209 A Primary Examiner-Donald R. Schran Attorney, Agent, or FirmH0lman & Stern [5 7 ABSTRACT In each of the intersections between the outer surface of a raw log and a plurality of longitudinal sectional planes passing through the center axis of the log, that point which is nearest the center axis is detected, and the log is so cut that, in each of the sectional planes, all points in the resulting outer line are at the same distance from the center axis as the above mentioned nearest point, whereby the raw log is preshaped into a columnar shape of the same coaxial cross section over the entire length thereof. By rotary cutting this preshaped log, rectangular veneer pieces without waste edge parts can be obtained before the log becomes a true circular cylinder.

3 Claims, 17 Drawing Figures PAIENIEDnmzzmu mums FIG. 16

METHOD AND APPARATUS FOR PRESHAPING RAW LOGS BACKGROUND OF THE INVENTION This invention relates generally to processing of timber logs to produce useful pieces therefrom and more particularly to an original and advanced method for preshaping a raw log into a columnar shape of the same coaxial cross section over the entire length or a specific length of the log.

PRIOR ART I-Ieretofore, raw logs to be rotary cut on a veneer lathe have been first debarked by manual work or by means of a machine and then rotary cut by means of a cutting blade 1 of a lathe as indicated in FIG. I, which is an exploded perspective view illustrating rotary cutting in the prior art.

However, since each raw log 2 has an infinitely varying form with a great variety of sectional profiles, several irregular pieces of veneer 3 including useless waste parts 4 must be unavoidably out before the timber stock becomes a true circular cylinder. In order to utilize these irregular veneer pieces as crossbands or core material in plywoods or for some other profitable purpose, they must be cut by means of a cutting device such as a clipper 5. Such a process requires an extremely great amount of time and labor.

SUMMARY- OF THE INVENTION It is an object of this invention to overcome the above described difficulty by preshaping the log beforehand into a columnar shape thereby to produce rotary-cut veneer sheets of rectangular shape, that is, with edges in the width direction that are perpendicular to the edges in the longitudinal direction.

According to this invention, briefly summarized, there is provided a method of preshaping a raw log into a columnar shape of the same coaxial cross section perpendicular to the center axis of the log over the entire length thereof, or a specific partial length thereof, which method comprises detecting that point in each of the intersections between the outer surface of the log and a plurality of longitudinal sectional planes passing through the center axis which is nearest the center axis and cutting the log so that, in each of the sectional planes, all points in the resulting outer line are at the same distance as the above mentioned nearest point from the center axis.

The nature, principle, and utility as well as further features ofthis invention will be apparent from the following detailed description with respect to preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings;

FIG. 1 is an exploded perspective view showing an example of rotary cutting of a timber log according to the prior art;

FIG. 2 is a similar perspective view showing one example of rotary cutting of a log according to this invention;

FIGS. 3 and 4 are perspective views, and FIG. 7 is an elevation viewed in the direction of work flow, indicating the manner in whichv guide grooves are formed in an unprocessed log prior to preshaping thereof;

FIGS. 5 and 6 are perspective views, and F IG. 8 is an elevation viewed in the work flow direction, indicating the manner in which a log is preshaped with one guide groove;

FIG. 9 is a schematic diagram indicating the essential organization of another embodiment of the invention;

FIGS. 10 and 11 are a side elevation and an elevation viewed in the direction of work flow showing one example of apparatus for debarking and preshaping logs according to the invention;

FIGS. 12 and 13 are views similar to FIGS. 10 and 12 showing another example of apparatus for debarking and preshaping logs according to the invention;

FIG. 14 is a side elevation showing one example of apparatus provided with a guide groove forming device at a point upstream in the work flow path from the debarking and preshaping device;

FIG. 15 is a perspective view showing one example of debarking cutters;

FIG. 16 is a perspective view showing the essential parts of one example of guide groove forming device; and

FIG. I7 is an elevation viewed in the work flow direction showing the guide groove forming device used in the apparatus shown in FIG. 14.

DETAILED DESCRIPTION Referring first to FIG. 2, indicating the principle of the invention, a raw log (not shown) is preshaped beforehand into a preshaped log 13 of a columnar shape as illustrated, and then this preshaped log 13 is rotary cut on a veneer lathe to produce rotary-cut veneer sheets 6 of rectangular shape, that is, with parallel edges in the width direction that are perpendicular to parallel edges in the longitudinal direction. Cross cuts at suitable places are made by means of a scribing blade 7 in the instant example as in the conventional process indicated in FIG. 1.

In a first specific example of the invention as shown in FIGS. 3, 4, and 7, a guide groove forming device, generally designated by reference numeral 8, is used first to form guide grooves 9 of suitable width around the entire peripheral outer part of a raw log 2. Next, by means of a shaping cutter 11 having a non-cutting contact surface 10 for contacting the bottoms of the guide groove 9, whereby the advance of the shaping cutter is limited, the remaining parts 12 are cut away. As a result, a preshaped log 13 of a columnar shape as indicated in FIG. 4 is obtained.

In another example of this invention as indicated in FIG. 9, suitable detectors 14 such as a battery of limit switches are used in place of the guide groove forming device described above and are placed in contact with the outer surface of a raw log 2, and a preshaping cutter 15 is advanced up to the depth of the deepest concavity of the various rotating surface positions of the raw log 2 which have been thus detected. As a result, the raw log 2 is preshaped into a log 13 of columnar form as indicated in FIG. 4.

Nest, examples of guide groove forming devices suitable for practicing the method of this invention as indicated in FIGS. 3, 4, and 7 will now be described in entirety with reference to FIGS. 10, 1 1, 12, and 13.

A device generally designated by reference numeral 16 for grasping, carrying, and turning logs includes, in the example illustrated in FIGS. 10, and 11, a frame having two horizontal, parallel, and spaced-apart beams 17, 17 disposed respectively opposite lateral sides of the device, with each beam 17 supporting a pair of spaced apart bearings 18, 18 respectively opposed to the pair of bearings 18, 18 on the other beam 17. These four bearings rotatably support two cross shafts 19, 19 spaced apart in parallelism and orientated horizontally and perpendicularly to the beams 17, 17.

Each of the cross shafts 19, 19 supports two arms 21, 21 swingably suspended therefrom at points near respective ends of the shaft and inside of the beams 17, 17. One of the cross shafts 19, 19 also supports at one of its ends a lever 20 fixed at one end to the shaft at a point outside of the corresponding beam 17. Thus, four arms 21 are suspended from the two cross shafts 19, 19. The two arms 21, 21 suspended from each cross shaft 19 support at their lower ends a swinging cross shaft 22.

The two cross shafts 22 rotatably and slidably support two log holding heads or stocks 23, 23, which are disposed on opposite lateral sides of the device and can slide along the cross shafts 22 to approach or separate from each other, being controllably actuated as described hereinafter. The stocks 23, 23 at their lower parts rotatably support horizontal centers or spindles 24, 24 mutually opposed in coaxial alinement and having toothed inner jaws for holding a log therebetween.

On each lateral side of the device, the beam 17 together with its bearings 18, 18, the two arms 21, and the part of the stock 23 between the cross shafts 22, 22 form a four-bar linkage of parallelogram shape. The other or distal end of the above mentioned lever 20 is coupled to the outer end of the piston rod of a hydraulic cylinder 20a pivotally supported by the frame beam 17. Accordingly, all of the four arms 21 can be actuated to swing in unison by the extension and retraction of the piston rod of the hydraulic cylinder 20a, whereby the stocks 23, 23 on both sides can be moved between positions directly above a centering bedplate 25 for the unprocessed log 2 and a receiving bedplate 26.

In the example illustrated in FIGS. 12 and 13, trucks or trolleys 27, 27 are supported on wheels 28, 28 rollable on and along two parallel, horizontal beams 17, 17 of the frame, which are disposed on respectively opposite lateral sides parallel to the direction of travel of the log. The beams l7, 17 are provided on their upper surfaces with gear-tooth racks 31 fixed in parallel thereto. Pinions 30, rotatably supported on the trolleys 27, 27 and driven by motive power means 29 are meshed with respective racks 31.

At their lower parts, the trolleys 27, 27 support two cross shafts similar to the cross shafts 22 in the preceding example. The various parts including the stocks 23, 23 supported on these cross shafts are similar to those in the preceding example. Thus, by operating the motive power means 29 in the forward and reverse directions, the trolleys 27, 27 and the stocks 23, 23 suspended therefrom can be moved between positions directly above the centering bedplate 25 and directly above the receiving bedplate 26.

A block structure 33 is slidably supported on the cross shafts 22, 22 between the two stocks 23, 23 and is controllably positioned in the transverse direction (parallel to the cross shafts 22, 22) by a hydraulic cylinder 32. This block 33 is coupled to the stocks 23, 23 by hydraulic cylinder and piston units 35 and 34, which operate to pull together and push apart the stocks 23, 23, whereby a raw, unprocessed log 2 can be grasped between the jaws of the center spindles 24, 24 and then released as desired. One of the center spindles 24 can be rotated by power from a driving mechanism including a motive power means 36 mounted on or within the corresponding stock 23.

Between the centering bedplate 25 and the receiving bedplate 26, there is provided a preshaping device generally designated by the reference numeral 37 (FIGS. 10 and 11) and having a base structure 38 on which the following mechanism is mounted. The base 38 has two bearings 39, 39 and two bearings 40, 40 all lying in one horizontal plane with a rectangular, spaced-apart relation and rotatably supporting two parallel shafts 41 and 42, on which a frame 43 and arms 44 are swingably supported. The frame 43 at its distal end supports a shaping cutter 46 having a contacting member 45; while the arms 44 at their distal ends support debarking cutters 47.

The frame 43 and the arms 44 can be respectively actuated by hydraulic cylinders 48 and 49 anchored at their cylinder ends to the base 38, whereby the shaping cutter 46 and the debarking cutter 47 can be brought into contact with or separated from a raw, unprocessed log 2 held by the log grasping, carrying, and turning device 16.

While the log grasping, carrying, and turning device 16 in the above described examples of the invention is a unitary mechanism, it is not so limited in arrangement. For example, this device may comprise a first mechanism for grasping and carrying a log and a second mechanism constructed separately from the first mechanism and operating to receive the log from the first mechansim and to turn the log.

In still another example of the invention as illustrated in FIG. 14, the arrangement shown in FIG. 13 wherein the log guide groove forming device 8 is mounted on the cross shafts 22 supporting the stocks 23, 23 is replaced by an arrangement wherein a log guide groove forming device 50 of another type is installed between the log centering bedplate 25 and the log preshaping device 37 so as to form the guide groove 9 from below the unprocessed log 2.

While not indicated in the drawings, it is also possible to provide suitably and selectively a log guide groove forming device 50 in the same manner between the log centering bedplate 25 and the log preshaping device 37 also in the example shown in FIG. 11 and, further, the log guide groove forming device 8 shown in FIGS. 11 and 13 in an upside-downjuxtaposition to be supported by a base structure between the log centering bedplate 25 and the log preshaping device 37.

The bark chips 52 and the wood chips 53 cut by the debarking cutters 47 and the shaping cutter 46 are carried toward the lateral sides by a chip conveyer 51 adapted to travel in either direction, carrying the bark chips 52 to a bark chip conveyor 54 and the wood chips 53 to a wood chip conveyor 55.

The centering bedplate 25 has at its upper part a retaining surface for receiving an unprocessed log 2 and is provided with a ram 25a by which it can be moved adjustably in the vertical direction and with a hydraulic cylinder 25b by which it can be moved in the left-andright direction as viewed in FIGS. 10 and 12. The receiving bedplate 26 has, at its upper part, a retaining surface for receiving a log which has been processed and is provided with a ram 26a by which it can be adjustably moved in the vertical direction.

In another example of the debarking cutters 47 as illustrated in FIG. 15, a shaft 57 supports a plurality of debarking cutter toothed wheels 47a in side-by-side coaxial arrangement, with each toothed wheel 4'7a being provided with a mechanism including a plurality of springs 56 whereby each toothed wheel undergoes a displacement relative to the axis of the shaft 57 in conformance with the peripheral contour of the log. Accordingly, each cutter wheel 47a is caused to undergo an independently suspended action similar to that of the hydraulic cylinder 49.

One unit of a guide groove forming device 8, not shown in FIGS. II and 13, will now be described in detail with reference to FIG. 16. Two brackets 58, 58 are supported in spaced apart relation on one of the aforedescribed cross shafts 22 and support a horizontal beam 59 fixed at its ends to the rear parts of these brackets thereby to form a rigid frame. Coaxial bearings 66, 60 are respectively fixed to the lower parts of these brackets 58, 58 and rotatably support a horizontal shaft 61, which is parallel to the shaft 22.

The shaft 61 rotatably supports three spaced apart levers 64, 64a, and 64b at intermediate points thereof. These levers at their ends on one side of the shaft 61 rotatably support respective profile following rollers 62, 62a and 62b for contacting respective peripheral surface parts of an unprocessed log 2. The other ends of these levers 64, 64a, and 64b are respectively pin connected to the outer ends of the piston rods of hydraulic cylinders 63, 63a, and 63b, which are mounted on the aforementioned beam 59.

Arms 65, 65a, and 65b with laterally extending bent ends are respectively fixed to the shaft 61 in the vicinity of the levers 64, 64a, and 64b, any of which, upon contacting the bent end of its corresponding arm causes the shaft to rotate. The shaft 61 at a suitable part thereof further supports the proximal part of a support lever 69 rotatably supporting at its outer end, by means bearing 66, the horizontal shaft of a groove forming cutter 67. This support lever 69 has an arm fixed thereto and pin connected at its outer end to the outer end of the piston rod of a hydraulic cylinder 68 mounted on the beam 59. The shaft of the cutter 67, and therefore, the cutter, are rotatable by a motive power means 70 mounted on the support lever 69 by way of power transmission means such as pulleys and an endless belt.

One unit of a guide groove forming device 50, not shown in FIG. I4, will now be described in detail with reference to FIG. 17. This device 50 has a base or bed 71 on which are mounted a suitable number, e.g., three, of upright hydraulic cylinders 72, 72a, and 72b having rams 73, 73a, and 74b, the outer or upper ends of which are fixed to lower flanged ends 76, 76a, and 74b of vertical support structures 75, 75a, and 75b rotatably supporting at their upper ends profile following rollers 74, 74a, and 74b for contacting respective peripheral parts of an unprocessed log 2 held and rotated by center spindles 24.

The flanged parts 76, 76a, and 76b of the support structures 75, 75a, and 75b support a'lift platform 77, on which is mounted a guide groove forming cutter 79 driven by a motive power means 78. The lower surface of the lift platform at its ends on the lateral sides of the device are fixed to the upper ends of rams 81, 81 of upright hydraulic cylinders 80, 60, which operate in a manner such that, when the profile following rollers 74, 74a, and 74b are forced downward by projecting convexities of the surface of the log 2, at least one of the flanged parts 76, 76a, and "76b of the support structures '75, a, and 75b is always contacting the lower surface of the lift platform 77.

Furthermore, a leveling device 82 of the following organization is provided for raising and lowering the lift platform 77 while its attitude is continually maintained level, without inclination in the transverse direction (i.e., the left and right direction in FIG. 17.

The lift platform 77 is provided near the four corners thereof on the upper surface thereof with bearings 83, 83 and 84, 84 fixed thereto and on the lower surface thereof with bearings 83a, 83a and 84a, 84a, fixed thereto. These bearings rotatably support four transverse shafts 85, 85 and 65a, 65a fixedly supporting at their ends chain wheels 86, 86 and 86a, 66a on one lateral side (the left side as viewed in FIG. 18) and chain wheels 87, 87 and 87a, 67a on the opposite lateral side.

The aforementioned bed 71 is provided at its four corners with respective upright posts 88, 88 and 88a, 88a. On each lateral side, for example, on the left side as viewed in FIG. 17, a chain anchored at one end thereof to the top of the post 88a is passed downward, reeved around a lower chain wheel 86a, passed upward, reeved around an upper chain wheel 86, and passed downward to be anchored by way of a turnbuckle 900 to the bed 71. Similarly, on the same lateral side, another chain anchored at one end thereof to the top of the post 88 is passed downward, reeved around the other lower chain wheel 86a, passed upward, reeved around the other upper chain wheel 86, and passed downward to be anchored by way of a turnbuckle 90 to the bed 7ll.

The devices of the above described organization ac cording to this invention operate as described below.

In the case of the examples illustrated in FIGS. 10, ll, 12, and 13, the unprocessed log 2, which has been conveyed by the unprocessed log conveyer is transferred onto the log centering bed plate 25, where centering is carried out by raising or lowering the ram 25a and operating the hydraulic cylinder 25b. Thereafter, the hydraulic cylinder 20a is activated to swing the stocks 23, 23 to a position above the centering bedplate where the center spindles 24, 24 can grasp the unprocessed log 2. The hydraulic cylinders 34 and 35 are then operated to pull together the stocks 23, 23 and thereby to cause the center spindles 24, 24 to grasp the log 2. The hydraulic cylinder 20a is then operated again to bring the log 2 to the position above the log shaping device 37 and to hold the same in position for debarking and shaping.

In the case of the example illustrated in FIGS. 12 and 13, the pinion 30 meshed with the rack 31 is driven by the motive power means 29 thereby to move the stocks 23, 23 horizontally and to stop the same above the log shaping device 27 (FIG. 14). Here, the surface of the unprocessed log 2, which is rotated by the motor 36 is contacted by the profile following rollers 62, 62a, and 62b pressed thereagainst by the levers 64, 64a, and 64b actuated by the hydraulic cylinders 63, 63a, and 63b of the log guide groove forming device 8 as shown in detail in FIG. 16.

For the purpose of illustration, it will be assumed that, of these profile following rollers 62, 62a, and 62b, the roller 62a, for example, is in a position which is the nearest to the center axis of the unprocessed log 2. Then, the lever 64a of this roller 62a pushes against the arm 65a thereby to turn the shaft 61 in the arrow direction A in the FIG. 16. Accordingly, the groove forming cutter 67 cuts the surface of the log 2 in accordance with the movements of the profile following roller 62a.

Since the log 2 is rotating, the levers 64, 64a, and 64b are rocking continually as their rollers 62, 62a, and 62b follow the concavities and convexities of the log surface in their respective paths around the periphery of the log. At the same time, the hydraulic cylinder 68 is imparting to the support lever 69 a lifting force which is always less than the pressing force of the profile following rollers 62, 62a, and 62b against the log 2. Consequently, since the shaft 61 is urged to rotate in the direction B, and the arms 65, 65a, and 65b are also tending to rise, at least one thereof is always in contact with the lever 64, 64a, or 64b.

By thus causing the log 2 to rotate through one or two revolutions, it is possible to form a guide groove 9 in accordance with those points which, in respective lines of intersection of sectional planes passing through the center axis of the log and the outer peripheral surface of the log over the entire surface, are the nearest to the center axis.

In the case of the example illustrated in FIG. 14, the unprocessed log 2 is once stopped above the guide groove forming device 50 disposed at an intermediate point in the path of the centered log 2 to the position above the shaping device 37, and the guide groove forming step is carried out. In this case, as indicated in detail in FIG. 17, the flanged parts 76, 76a, and 76b of the support structures 75, 75a, and 75b are raised by the rams 73, 73a, and 73b of the hydraulic cylinders 72, 72a, and 72b, and the profile following rollers 74, 74a, and 74b are placed in contact with the log 2.

If, as an assumption, the roller 74a of the profile following rollers 74, 74a, and 74b is at a position nearest the center axis of the log 2, the flanged part 76a of its support structure 75a will contact the lower surface of the lift platform 77. The groove forming cutter 79 mounted on this lift platform 77 and driven by the motive power means 78 will thereupon cut the surface of the log 2 in conformance with the movements of the profile following roller 74a.

Since the log 2 is rotating, the rollers 74, 74a, and 74b ascend and descend in conformance with the concavities and convexities of the log surface along their respective paths thereon. Consequently, the flanged parts 76, 76a, and 76b of the support structures 75, 75a, and 75b also are ascending and descending, but since a downward force which is always less than the pressing force of the rollers 74, 74a, and 74b against the log 2 is being imparted by the hydraulic cylinder 80 to the lift platform 77, at least one of the flanged parts 76, 76a, and 76b is always contacting the lift platform 77.

By thus rotating the log 2 through one or two revolutions, it is possible to form a guide groove 9 in accordance with those points which, in respective lines of intersection of sectional planes passing through the center axis of the log and the outer peripheral surface of the log over the entire surface, are the nearest to the center axis.

Furthermore, even in the case where the diameter of the unprocessed log 2 differs in its longitudinal direction, i.e., in the transverse direction of the work flow, the aforedescribed leveling device operates to cause the lift platform 77 to ascend and descend always with a level, horizontal attitude relative to the center axis of rotation of the log. Accordingly, an accurate guide groove 9 can always be formed.

Upon completion is this groove forming process step, the log guide forming device 8 is retracted upward by the hydraulic cylinders 63, 63a, and 63b in the example apparatus illustrated in FIGS. 10 through 13. In the example shown in FIG. 14, the stocks 23, 23 are moved further by the motive power means 29 to a position above the log shaping device 37, where the shaping cutter 46 having the contacting member 45, which upon contacting the bottom of the guide groove 9 stops the advance of the shaping cutter 46, is pressed against the log 2 by the hydraulic cylinder 48. The cutter 46 is then rotated by suitable means (not shown) thereby to shape the log in conformance with the guide groove 9, whereby a preshaped log 13 of the columnar shape shown in FIG. 4 is obtained.

In this case, debarking may be carried out, depending on the necessity, previously to the shaping step by the shaping cutter 46. This debarking step may be carried out by operating the hydraulic cylinder 49 to bring the debarking cutters 47 into contact with the log 2 in conformance with the peripheral contour thereof, rotating these debarking cutters 47 by suitable means (not shown), and, at the same time, operating the motive power means 36 to rotate the driving center spindle 24.

Depending on the necessity in this operation step, it is also possible carry out uniform debarking over the entire peripheral surface of the log 2 by moving the block 33 by means of the hydraulic cylinder 32 thereby to vary the position where the cutter contacts the log. The bark chips 52 thus peeled off are carried by way of the chip conveyer 51 to the bark chip conveyer 54.

For the debarking cutters 47, the cutter shown in FIG. 15 can be used with suitably selected specifications. In this case, it becomes unnecessary to provide a hydraulic cylinder 49 for each of the debarking cutters 47, and a large number of debarking cutters 47 are secured to the shaft 57, which is raised and lowered by means such as a hydraulic cylinder to cause the cutters to contact the log 2.

The unprocessed log 2 can be shaped directly into columnar form in the following manner by means of the shaping cutter 15 without first forming a guide groove 9. In this case, the process steps up to the point where the unprocessed log 2 is centered and then conveyed to the position above the log shaping device are the same as those of the examples illustrated in FIGS. 10 through 13.

As indicated in FIG. 9, the surface of an unprocessed log 2 which has been placed in position above the log shaping device 37 is contacted by sensors, such as a plurality of limit switches, of suitable detectors 14, 14 to detect that point on a line in the longitudinal direction of the log constituting an intersection of a sectional plane passing through the log center axis and the log outer peripheral surface which is nearest the center axis. Then, in the sectional plane of this point, this point is taken as a reference datum, and the, other parts are cut away in parallel to the center axis by means of the shaping cutter 15. By carrying out this procedure over the entire peripheral surface of the unprocessed log 2, the log can be rendered into a log 13 shaped into a columnar shape as indicated in FIG. 4.

In this case also, debarking may be carried out with a debarking cutter 47, previously to shaping by means of the shaping cutter 15 in accordance with necessity similarly as in the above described case wherein shaping is carried out by forming a guide groove 9.

In the foregoing description, the shaping cutter 46 is made of two parts, whereby the resulting preshaped log 13 is shaped separately on the left and right halves with a division point at the mid-point in the longitudinal direction of a single log as indicated in FIG. 4. However, in the case where the log is of short length as in the production of veneers to be utilized as crossbands or core material of plywoods, and one of each of a cutter 15 (46), guide groove forming device 8, and suitable detecting means such as limit switches are used as shown in FIGS. 5, 6, and 8. It is also possible to shape a single log so that it has the same columnar shape over its entire length as indicated in FIG. 6.

Furthermore, in some cases, three or more sets each of three or more of shaping cutters 15 (46), guide groove forming devices 8, and suitable detection means 14 such as limit switches can be provided are suitably and selectively utilized to shape a single log into a configuration of a plurality of parts.

By the practice of this invention, as described above, it is possible to cut veneer pieces without unnecessary parts in the rotary cutting process for producing veneer pieces. Accordingly, the trimming off and processing of unnecessary parts of veneer pieces, which having been carried out with an extremely great amount of time and labor, can be eliminated. Furthermore, since foreign matter, such as gravel, sand, and shells, adhering to the raw log can be removed, the wear and damage of cutting tolls used in the rotary cutting process can be greatly reduced. As a result, the work efficiency and yield in the rotary cutting process can be greatly increased.

We claim:

A method of preliminarily shaping a raw log into columnar shape for subsequent economical rotary cutting thereof to produce veneer pieces having a definite rectangular shape, which comprises detecting that point in each of the intersections between the outer surface of said log and plurality of longitudinal sections passing through the center axis of the log which is nearest said center axis and cutting away the outer surface part of the log along element lines each alined in parallel to the center axis and passing through a respective one of said detected points while carrying out profiling based on said detected points thereby to preshape the log into a columnar shape of substantially the same planar shape in any cross section thereof.

2. A method of preliminarily shaping a raw log in a plurality of longitudinal contiguous parts for subsequent economical rotary cutting thereof to produce veneer pieces having a definite rectangular shape which comprises: geometrically dividing the log into a plurality of longitudinally contiguous parts; detecting, in each of said parts, that point in each of the intersections between the outer surface of the log and a plurality of longitudinal sections passing through the center axis of said part which is nearest the center axis; and, in each part, cutting away the outer surface part of the log along element lines each alined in parallel to the center axis and passing through a respective one of the points thus detected, while carrying out profiling based on said detected points thereby to preshape each part into a columnar shape of substantially the same planar shape in any cross section thereof.

3. A method of preshaping a raw log into columnar shape for economical rotary cutting thereof, which comprises detecting that point in each of the intersections between the outer surface of said log and a plurality of longitudinal sections passing through the center axis of the log which is nearest said center axis and cutting away the outer surface part of the log along element lines each alined in parallel to the center axis and passing through a respective one of said detected points while carrying out profiling based on said detected points thereby to preshape the log into a columnar shape of substantially the same planar shape in any cross section thereof, in which said profiling working comprises the steps of cutting a guide groove around the outer surface of the log by profiling said outer surface in accordance with the detected points included in said respective intersections and then profiling the outer surface part of the log in accordance with the form of said cut guide groove. 

1. A method of preliminarily shaping a raw log into columnar shape for subsequent economical rotary cutting thereof to produce veneer pieces having a definite rectangular shape, which comprises detecting that point in each of the intersections between the outer surface of said log and plurality of longitudinal sections passing through the center axis of the log which is nearest said center axis and cutting away the outer surface part of the log along element lines each alined in parallel to the center axis and passing through a respective one of said detected points while carrying out profiling based on said detected points thereby to preshape the log into a columnar shape of substantially the same planar shape in any cross section thereof.
 2. A method of preliminarily shaping a raw log in a plurality of longitudinal contiguous parts for subsequent economical rotary cutting thereof to produce veneer pieces having a definite rectangular shape which comprises: geometrically dividing the log into a plurality of longitudinally contigUous parts; detecting, in each of said parts, that point in each of the intersections between the outer surface of the log and a plurality of longitudinal sections passing through the center axis of said part which is nearest the center axis; and, in each part, cutting away the outer surface part of the log along element lines each alined in parallel to the center axis and passing through a respective one of the points thus detected, while carrying out profiling based on said detected points thereby to preshape each part into a columnar shape of substantially the same planar shape in any cross section thereof.
 3. A method of preshaping a raw log into columnar shape for economical rotary cutting thereof, which comprises detecting that point in each of the intersections between the outer surface of said log and a plurality of longitudinal sections passing through the center axis of the log which is nearest said center axis and cutting away the outer surface part of the log along element lines each alined in parallel to the center axis and passing through a respective one of said detected points while carrying out profiling based on said detected points thereby to preshape the log into a columnar shape of substantially the same planar shape in any cross section thereof, in which said profiling working comprises the steps of cutting a guide groove around the outer surface of the log by profiling said outer surface in accordance with the detected points included in said respective intersections and then profiling the outer surface part of the log in accordance with the form of said cut guide groove. 